How do I show/hide Cancelled Patient Appointments on the Schedule?

You can show or hide cancelled appointments on your schedule by going to Settings, General, System, Scheduling.  Under the Dashboards section, beside the Highlight & Display Cancelled Appointments, select Yes or No and Save.
Cancellation Report:

You can create a list of appointments by going to the Report tab. Under the Scheduling heading select Cancellations by Practitioner. You can select to create a report on any or all of the cancellation reasons.